Diet xylo-oligosaccharide supplementation improves growth performance, immune function, and intestinal health of broilers

The effects of xylo-oligosaccharides (XOS) on broiler growth performance, immune function, and intestinal health were investigated. A total of 540 one-d-old Arbor Acres Plus broilers were randomly divided into 5 groups with 6 replicates per group and 18 chickens per replicate. Broilers in the control (CON) group received a corn-soybean meal based basal diet, those in the antibiotics (ANT) group received the basal diet plus 500 mg/kg oxytetracycline, and those in XOS groups received the basal diet plus 150, 300, or 450 mg/kg XOS. Compared with CON, the body weight at 42 d and average daily gain from 1 to 42 d were signi ficantly increased in the 150, 450 mg/kg XOS-added and ANT groups ( P = 0.018), and the relative expression of claudin-1 and ZO - 1 mRNA in the ileum was signi ficantly higher in the 300 and 450 mg/kg XOS-added groups ( P < 0.001). The feed conversion ratios ( P < 0.001) and abdominal fat rates ( P = 0.012) of broilers from 1 to 42 d of age were signi ficantly lower in all XOS-added groups than in the control group. Splenic index ( P = 0.036) and bursa of Fabricius index ( P = 0.009) were signi ficantly better in the ANT group and each XOS-added group than in the control group. Compared to CON and ANT, serum IgA ( P = 0.007) and IgG ( P = 0.002) levels were signi ficantly higher in the 300 mg/kg XOS-added group, and the relative abundance of short-chain fatty acid-producing genera ( Alistipes ) was also signi ficantly higher ( P < 0.001). Meanwhile, ileal villus height ( P < 0.001) and ratio of villus height to crypt depth (V:C) ( P = 0.001) were signi ficantly increased in XOS-added broilers. In analysis of relationships between cecal microbes and the physical barrier of the gut, [Ruminococcus]_torques_group was positively correlated with mRNA expression of ileal ZO -1 and claudin-1 ( P < 0.05), and Bacteroides was positively correlated with increased ileal villus height and V:C ( P < 0.05). Overall, XOS addition to broiler diets improved growth performance, promoted intestinal health by enhancing intestinal barrier function and regulating cecal microbiota diversity, and had positive effects on immunity. (c) 2024 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync-nd/4.0/).